Motor armature having an integral driving surface

ABSTRACT

An integral capstan and tubular printed circuit armature for use in an electrodynamic machine, wherein individual printed circuit armature winding conductors are formed on both the inside and the outside surface of an epoxy-fiberglass tube. The inner and outer conductors are electrically interconnected at the ends of the tube. The annular band of the metallic inter-connected tabs at one end of the tube extend beyond the area of interconnection and physically attach to and mount a second fiberglass tube which is the mounting portion of the capstan.

[451 July 18, 1972 United States Patent Parker ....3l0/236 ...3l0/266 X 310/162 m hhu .m.w FFG MWWH 9999 mmmw 7266 47 5 3 ,9 9028 9938 15 1333 m b E o GC WA m m m. ms M L k a TM P E D W .m h

Rm 0G m T m 0 e N V MI .m M .4 U U 73 Assi nee: International Business Ma hines Corpor l 1 g on, Armonk c a Primary Examiner-J. D. Miller Feb. 19, 1971 Assistant Examiner-R. Skudy [22] Filed:

Attorney-Hanifin and Jancin and F. A. Sirr [57] ABSTRACT An integral capstan and tubular printed circuit armature for [21] App]. No.:

[52] US. Cl.................................310/236,33l:)(;%% 3212(g/1l988 use in an clectmdynamic machine, wherein individual primed I 5 H In 6 13/04 circuit armature winding conductors are formed on both the inside and the outside surface ofan p y g tube The [58] Field ofSearch......v...........310/236, 266, 162, 198, 207,

- 310/264 66 226/188 inner and outer conductors are electrically interconnected at the ends of the tube. The annular band of the metallic interconnected tabs at one end of the tube extend be yond the area of interconnection and physically attach to and mount a [56] References Cited UNITED STATES PATENTS second fiberglass tube which is the mounting portion of the capstan.

Henry-Baudot.................. ....310/266 3,209,187 9/1965 Ange1e...................................310/266 7Claims,4Draw1ngF1gures PATENIEDJHU IM 3.678.313

' sum 1 0F 2 NTOR JOH RKER MOTOR ARMATURE HAVING INTEGRAL DRIVING SURFACE BACKGROUND AND SUMMARY OF THE INVENTION The present invention relates to an improved armature of a type including, as an integral portion thereof, a cylindrical driving element or capstan. A prior art integrated tubular armature-capstan structure is disclosed in U.S. Pat. No. 3,490,672, issued to Gene A. Fisher and Howard A. Van Winkle.

The preferred embodiment of the present invention, without limitation thereto, utilizes a printed circuit armature and method of making as disclosed in my copending United States patent application, Ser. No. 6,816, filed Jan. 29, 1970, now U.S. Pat. No. 3,623,220.

The preferred embodiment of the present invention is a tubular armature and utilizes, as a portion of the capstan, an epoxy-fiberglass tube which is axially spaced from the likematerial tube disclosed in my above-mentioned copending patent application. When the printed circuit armature winding conductors are formed in accordance with the teachings of that invention, the metallic interconnect tabs are axially extended beyond the annular band where electrical interconnect is achieved, to bridge the annular gap between the epoxyfiberglass tube which forms the armature and the second fiberglass tube which is a part of the capstan. Specifically, the inner conductors of the armature extend axially over the inner circumference of the second tube, and the outer conductors similarly bridge the annulus and extend axially over the outer circumference of the second tube.

The foregoing and other features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 disclose an integral capstan motor armature such as is disclosed in the above-mentioned patent to G A. Fisher et al., which utilizes the tubular armature of the present invention,

FIG. 3 is an enlarged section view of the armature of FIG. 1, showing the manner in which the interconnect tabs mount the capstan drive tube to the armature, and

FIG. 4 shows a modified form of capstan.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 disclose a capstan motor for use in a magnetic tape unit, this capstan motor having an integral cylindrical driving element, or capstan, mounted directly on one end of a low inertia, printed circuit, tubular armature. A motor of this general type is disclosed in the above-mentioned patent to G. A. Fisher et al., and reference may be had to that patent for a detailed description of the structure of the motor. The basic elements of this motor consist of permanent magnets which are mounted in a cluster about tubular printed circuit armature 11. This armature surrounds a magnetic flux return path 12 which includes shafts 13 and 14 to facilitate the mounting of member 12 at a fixed, nonrotatable position within the motor structure. Armature 11 is rotatably mounted upon shafts l3 and 14 by means of bearings 15 and 16.

Bearing 15 is insulated from the electrical conductors on the inside circumferential surface of armature 11, whereas bearing 16 mounts the inside circumferential surface of capstan driving element 17 relative to shaft 14.

In FIG. 1, capstan driving surface 17 is shown cooperating with a section of magnetic tape 20, shown in phantom. Also, this figure discloses a disk 21 which forms a portion of an optical tachometer, which in turn is utilized in a digital velocity servomechanism (not shown) to control the speed of rotation of capstan 17.

Referring to FIG. 3, this view is an enlarged section of the armature of FIG. 1, showing the manner in which the interconnecting tabs of the armature winding mount the capstan drive surface 17 to one end of the armature.

Drive surface 17 is shown as a single thickness fiberglass tube. Normally, the tube carries a rubber-like drive surface to frictionally engage tape 20.

While the present invention can be used with any type of winding configuration, a wave-type winding is disclosed. The armature per se may be formed in accordance with the teachings of my above-mentioned copending patent application, wherein the inner and outer winding conductor configuration is formed on a fiberglass tube by means of an electroforrning process followed by a chemical etch to obtain the circuit pattern. Specifically, reference numeral 30 identifies a reinforced plastic tube such as a fiberglass/epoxy tube which supports copper electrical conductors 32 on the inner tubular surface thereof. The outer tubular surface is likewise covered by a plurality of conductors 33. The inner and outer conductors of this armature electrically interconnect at annular end portions 34 and 35 to form a plurality of interconnect tabs. At the capstan end of the annature, these individual conductors extend beyond interconnect portion 35 to engage the inner and outer tubular surfaces of the tubular fiberglass capstan driving element 17. Specifically, the mounting portion 40 of capstan 17 is a coaxial extension of fiberglass tube 31 which is axially displaced therefrom to form the annular space 35 wherein the interconnect tabs connect the inner and outer circuit conductors. The inner and outer conductors extend axially beyond the electrical interconnect portion 35 to form extending tabs 41 and 42. The tabs 41 circle the outside surface of tube 40 whereas the tabs 42 circle the inside surface of the tube. The function of these tabs 41 and 42 is to mechanically mount capstan 17 in a rigid nonvibratory manner on the end of tubular armature l 1 without obstructing the driving surface of capstan driving element 17.

FIG. 4 discloses a modified form of capstan 50 wherein the diameter of the capstan is substantially identical to the diameter of the fiberglass tube which forms the control tube of armature 51.

By way of example, a tubular armature constructed in accordance with the teachings of the present invention has been constructed having the following dimensions: the total length of the armature and capstan as viewed in FIG. 4 was 9.480 inches; the diameter of armature l l was 1.030 inches; the diameter of capstan 17 was 1.018 inches; the axial gap 35 between tubes 30 and 40 was 0.140 inches; the width of conductors 32 and 33, measured in a circumferential direction was 0.060 inches, the thickness of these conductors, measured in a radial direction, was 0.005 inches, and the circumferential space between these conductors was 0.011 inches; the thickness of fiberglass tubes 30 and 40, measured in a radial direction, was 0.008 inches. The portion of capstan 50 that engages and drives tape was formed by an additional sleeve having a thickness of 0.150 inches, this sleeve being secured to the outer surface of capstan 50 and included a rubber-like tape driving surface.

While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.

What is claimed is:

1. In a motor having stationary stator means, an armature rotatably mounted with respect thereto, and means for supplying electrical energy to the motor to produce rotating torque for the armature, an improved armature comprising;

an armature formed of an array of metallic winding conductors including an annular pattern of metallic interconnect tabs whereat the armature winding changes direction,

a cylindrical driving element constituting the rotational output means of the motor, said driving element having a driving interface on its circumference adapted to engage a load to be driven by the motor, and

means including said annular pattern of metallic interconnect tabs and excluding said driving interface mounting said driving element on said armature.

2. A motor as defined in claim 1 wherein said armature is a tubular armature including inner, central and outer concentric layers, the central layer being a tube of electrical insulating material which constitutes the mechanical support for the inner and outer layers, said inner and outer layers providing inner and outer armature winding patterns of electrical conductive metal, in each layer of which the individual conductors axially extend beyond the ends of said central layer and electrically connect to a conductor in the layer on the other side of said central layer, to form an annular pattern of metallic interconnect tabs at each end of said armature, and wherein a mounting portion of said driving element is supported by the interconnect tabs at one end of said tubular armature, said mounting portion being spaced from said driving interface.

3. A tubular armature for use as the rotor of an electric machine, comprising; 7

a tubular array of metallic winding conductors, including end tabs whereat the armature winding axially changes direction, and

a tubular driving element having a driving interface and a tubular mounting portion spaced from said driving interface and mounted on said end tabs at one end of said tubular array of winding conductors.

4. A tubular armature as defined in claim 3 wherein said metallic winding conductors are carried by an insulating tube.

5. A tubular armature as defined in claim 4 wherein said armature winding is formed of individual conductors which lie on both the inside and outside surfaces of said insulating tube and extend beyond each end of the insulating tube to form two annular arrays of end tabs, at each end tab of which an inner conductor connects to an outer conductor.

6. A tubular armature as defined in claim 5 wherein the mounting portion of said driving element is an insulating tube, and wherein the two conductors forming each of said end tabs at one end of said armature extend beyond the area of electrical interconnection to physically cooperate with said mounting portion and thereby mount said driving element in concentric axial alignment with said tubular armature.

7. A tubular armature as defined in claim 6 wherein the mounting portion of said driving element is substantially equal to diameter to said insulating tube, and wherein said two conductors forming each of said end tabs extend axially away from said armature to first electrically interconnect and then physically separate and continue to an axial direction, one of said conductors being attached to the outer surface of the mounting portion of said driving element and the other conductor being attached to its inner surface. 

1. In a motor having stationary stator means, an armature rotatably mounted with respect thereto, and means for supplying electrical energy to the motor to produce rotating torque for the armature, an improved armature comprising; an armature formed of an array of metallic winding conductors including an annular pattern of metallic interconnect tabs whereat the armature winding changes direction, a cylindrical driving element constituting the rotational output means of the motor, said driving element having a driving interface on its circumference adapted to engage a load to be driven by the motor, and means including said annular pattern of metallic interconnect tabs and excluding said driving interface mounting said driving element on said armature.
 2. A motor as defined in claim 1 wherein said armature is a tubular armature including inner, central and outer concentric layers, the central layer being a tube of electrical insulating material which constitutes the mechanical support for the inner and outer layers, said inner and outer layers providing inner and outer armature winding patterns of electrical conductive metal, in each layer of which the individual conductors axially extend beyond the ends of said central layer and electrically connect to a conductor in the layer on the other side of said central layer, to form an annular pattern of metallic interconnect tabs at each end of said armature, and wherein a mounting portion of said driving element is supported by the interconnect tabs at one end of said tubular armature, said mounting portion being spaced from said driving interface.
 3. A tubular armature for use as the rotor of an electric machine, comprising; a tubular array of metallic winding conductors, including end tabs whereat the armature winding axially changes direction, and a tubular driving element having a driving interface and a tubular mounting portion spaced from said driving interface and mounted on said end tabs at one end of said tubular array of winding conductors.
 4. A tubular armature as defined in claim 3 wherein said metallic winding conductors are carried by an insulating tube.
 5. A tubular armature as defined in claim 4 wherein said armature winding is formed of individual conductors which lie on both the inside and outside surfaces of said insulating tube and extend beyond each end of the insulating tube to form two annular arrays of end tabs, at each end tab of which an inner conductor connects to an outer conductor.
 6. A tubular armature as defined in claim 5 wherein the mounting portion of said driving element is an insulating tube, and wherein the two conductors forming each of said end tabs at one end of said armature extend beyond the area of electrical interconnection to physically cooperate with said mounting portion and thereby mount said driving element in concentric axial alignment with said tubular armature.
 7. A tubular armature as defined in claim 6 wherein the mounting portion of said driving element is substantially equal to diameter to said insulating tube, and wherein said two conductors forming each of said end tabs extend axially away from said armature to first electrically interconnect and then physically separate and continue to an axial direction, one of said conductors being attached to the outer surface of the mounting portion of said driving element and the other conductor being attached to its inner surface. 